1. Field of the Invention
The invention relates to a medical handpiece for driving rotational medical tools, the tool being connectable to a drive shaft which is driven by a turbine arranged in the handpiece with the aid of a pressure medium. In a preferred manner, the pressure medium is compressed air.
2. Related Technology
In the case of such a turbine handpiece, a turbine wheel is mounted so as to be freely rotatable in a substantially round turbine chamber. The pressure medium is supplied by means of a supply line which extends longitudinally in the handpiece, flows through an inlet opening in the turbine chamber onto the turbine wheel, rotates the turbine wheel and leaves the turbine chamber by means of an outlet opening and a removal line which connects thereto. The drive of the turbine is shut down through the closing of a valve in the supply line. As the handpiece is operated at very high speeds, the turbine wheel still runs on for a considerable time after the supply of pressure medium has been cut out, forcing the pressure medium out of the turbine chamber into the removal line and consequently acting as a pump. The negative pressure generated at the same time in the turbine chamber causes a suction effect among other things in air gaps in the region of the mounting for the medical tools or in the region of the bearing arrangement of the turbine wheel. This is undesirable as pathogens can be sucked into the regions of the handpiece where only inadequate disinfection is possible or, in the worst case, which cannot be reached by way of the usual disinfection measures.